diff --git a/src/pl/plpgsql/src/pl_comp.c b/src/pl/plpgsql/src/pl_comp.c
index 1300ea6a525..2d7844bd9da 100644
--- a/src/pl/plpgsql/src/pl_comp.c
+++ b/src/pl/plpgsql/src/pl_comp.c
@@ -2384,14 +2384,14 @@ plpgsql_finish_datums(PLpgSQL_function *function)
 
 /* ----------
  * plpgsql_add_initdatums		Make an array of the datum numbers of
- *					all the simple VAR datums created since the last call
+ *					all the initializable datums created since the last call
  *					to this function.
  *
  * If varnos is NULL, we just forget any datum entries created since the
  * last call.
  *
- * This is used around a DECLARE section to create a list of the VARs
- * that have to be initialized at block entry.  Note that VARs can also
+ * This is used around a DECLARE section to create a list of the datums
+ * that have to be initialized at block entry.  Note that datums can also
  * be created elsewhere than DECLARE, eg by a FOR-loop, but it is then
  * the responsibility of special-purpose code to initialize them.
  * ----------
@@ -2402,11 +2402,16 @@ plpgsql_add_initdatums(int **varnos)
 	int			i;
 	int			n = 0;
 
+	/*
+	 * The set of dtypes recognized here must match what exec_stmt_block()
+	 * cares about (re)initializing at block entry.
+	 */
 	for (i = datums_last; i < plpgsql_nDatums; i++)
 	{
 		switch (plpgsql_Datums[i]->dtype)
 		{
 			case PLPGSQL_DTYPE_VAR:
+			case PLPGSQL_DTYPE_REC:
 				n++;
 				break;
 
@@ -2427,6 +2432,7 @@ plpgsql_add_initdatums(int **varnos)
 				switch (plpgsql_Datums[i]->dtype)
 				{
 					case PLPGSQL_DTYPE_VAR:
+					case PLPGSQL_DTYPE_REC:
 						(*varnos)[n++] = plpgsql_Datums[i]->dno;
 
 					default:
diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c
index 1959d6dc424..fa4d573e50c 100644
--- a/src/pl/plpgsql/src/pl_exec.c
+++ b/src/pl/plpgsql/src/pl_exec.c
@@ -1184,7 +1184,6 @@ exec_stmt_block(PLpgSQL_execstate *estate, PLpgSQL_stmt_block *block)
 {
 	volatile int rc = -1;
 	int			i;
-	int			n;
 
 	/*
 	 * First initialize all variables declared in this block
@@ -1193,13 +1192,17 @@ exec_stmt_block(PLpgSQL_execstate *estate, PLpgSQL_stmt_block *block)
 
 	for (i = 0; i < block->n_initvars; i++)
 	{
-		n = block->initvarnos[i];
+		int			n = block->initvarnos[i];
+		PLpgSQL_datum *datum = estate->datums[n];
 
-		switch (estate->datums[n]->dtype)
+		/*
+		 * The set of dtypes handled here must match plpgsql_add_initdatums().
+		 */
+		switch (datum->dtype)
 		{
 			case PLPGSQL_DTYPE_VAR:
 				{
-					PLpgSQL_var *var = (PLpgSQL_var *) (estate->datums[n]);
+					PLpgSQL_var *var = (PLpgSQL_var *) datum;
 
 					/*
 					 * Free any old value, in case re-entering block, and
@@ -1241,7 +1244,7 @@ exec_stmt_block(PLpgSQL_execstate *estate, PLpgSQL_stmt_block *block)
 
 			case PLPGSQL_DTYPE_REC:
 				{
-					PLpgSQL_rec *rec = (PLpgSQL_rec *) (estate->datums[n]);
+					PLpgSQL_rec *rec = (PLpgSQL_rec *) datum;
 
 					if (rec->freetup)
 					{
@@ -1258,13 +1261,8 @@ exec_stmt_block(PLpgSQL_execstate *estate, PLpgSQL_stmt_block *block)
 				}
 				break;
 
-			case PLPGSQL_DTYPE_RECFIELD:
-			case PLPGSQL_DTYPE_ARRAYELEM:
-				break;
-
 			default:
-				elog(ERROR, "unrecognized dtype: %d",
-					 estate->datums[n]->dtype);
+				elog(ERROR, "unrecognized dtype: %d", datum->dtype);
 		}
 	}
 
diff --git a/src/pl/plpgsql/src/plpgsql.h b/src/pl/plpgsql/src/plpgsql.h
index 84485785370..39bd82acd19 100644
--- a/src/pl/plpgsql/src/plpgsql.h
+++ b/src/pl/plpgsql/src/plpgsql.h
@@ -407,8 +407,8 @@ typedef struct PLpgSQL_stmt_block
 	int			lineno;
 	char	   *label;
 	List	   *body;			/* List of statements */
-	int			n_initvars;
-	int		   *initvarnos;
+	int			n_initvars;		/* Length of initvarnos[] */
+	int		   *initvarnos;		/* dnos of variables declared in this block */
 	PLpgSQL_exception_block *exceptions;
 } PLpgSQL_stmt_block;
 
diff --git a/src/test/regress/expected/plpgsql.out b/src/test/regress/expected/plpgsql.out
index d6e5bc33536..29f9e86d560 100644
--- a/src/test/regress/expected/plpgsql.out
+++ b/src/test/regress/expected/plpgsql.out
@@ -5025,6 +5025,33 @@ select scope_test();
 (1 row)
 
 drop function scope_test();
+-- Check that variables are reinitialized on block re-entry.
+do $$
+begin
+  for i in 1..3 loop
+    declare
+      x int;
+      y int := i;
+      r record;
+    begin
+      if i = 1 then
+        x := 42;
+        r := row(i, i+1);
+      end if;
+      raise notice 'x = %', x;
+      raise notice 'y = %', y;
+      raise notice 'r = %', r;
+    end;
+  end loop;
+end$$;
+NOTICE:  x = 42
+NOTICE:  y = 1
+NOTICE:  r = (1,2)
+NOTICE:  x = <NULL>
+NOTICE:  y = 2
+ERROR:  record "r" is not assigned yet
+DETAIL:  The tuple structure of a not-yet-assigned record is indeterminate.
+CONTEXT:  PL/pgSQL function inline_code_block line 15 at RAISE
 -- Check handling of conflicts between plpgsql vars and table columns.
 set plpgsql.variable_conflict = error;
 create function conflict_test() returns setof int8_tbl as $$
diff --git a/src/test/regress/sql/plpgsql.sql b/src/test/regress/sql/plpgsql.sql
index 1c355132b77..07b6fc89716 100644
--- a/src/test/regress/sql/plpgsql.sql
+++ b/src/test/regress/sql/plpgsql.sql
@@ -4014,6 +4014,27 @@ select scope_test();
 
 drop function scope_test();
 
+-- Check that variables are reinitialized on block re-entry.
+
+do $$
+begin
+  for i in 1..3 loop
+    declare
+      x int;
+      y int := i;
+      r record;
+    begin
+      if i = 1 then
+        x := 42;
+        r := row(i, i+1);
+      end if;
+      raise notice 'x = %', x;
+      raise notice 'y = %', y;
+      raise notice 'r = %', r;
+    end;
+  end loop;
+end$$;
+
 -- Check handling of conflicts between plpgsql vars and table columns.
 
 set plpgsql.variable_conflict = error;